feat: single source of truth for app version from health check

Read version from the backend /api/health endpoint instead of
hardcoding from package.json at build time. Add About section
in Settings with link to the DZone design article.

frontend/src/features/feature-flags/store.ts

@@ -7,6 +7,7 @@ type DeploymentMode = 'self-hosted' | 'huggingface'
 
 interface HealthResponse {
   status: string
+  version?: string
   engine: ConversionEngine
   deploymentMode?: DeploymentMode
   maxPageCount?: number
@@ -41,6 +42,7 @@ export const useFeatureFlagStore = defineStore('feature-flags', () => {
   const deploymentMode = ref<DeploymentMode | null>(null)
   const maxPageCount = ref<number>(0)
   const maxFileSizeMb = ref<number>(0)
+  const appVersion = ref<string>(__APP_VERSION__)
   const loaded = ref(false)
   const error = ref<string | null>(null)
 
@@ -62,6 +64,7 @@ export const useFeatureFlagStore = defineStore('feature-flags', () => {
       deploymentMode.value = data.deploymentMode ?? 'self-hosted'
       maxPageCount.value = data.maxPageCount ?? 0
       maxFileSizeMb.value = data.maxFileSizeMb ?? 0
+      if (data.version) appVersion.value = data.version
       loaded.value = true
       error.value = null
     } catch (e) {
@@ -70,5 +73,15 @@ export const useFeatureFlagStore = defineStore('feature-flags', () => {
     }
   }
 
-  return { engine, deploymentMode, maxPageCount, maxFileSizeMb, loaded, error, isEnabled, load }
+  return {
+    engine,
+    deploymentMode,
+    maxPageCount,
+    maxFileSizeMb,
+    appVersion,
+    loaded,
+    error,
+    isEnabled,
+    load,
+  }
 })

frontend/src/features/settings/ui/SettingsPanel.vue

@@ -36,15 +36,43 @@
       <label class="setting-label">{{ t('settings.version') }}</label>
       <span class="setting-value">{{ version }}</span>
     </div>
+
+    <div class="setting-group">
+      <label class="setting-label">{{ t('settings.about') }}</label>
+      <a
+        href="https://dzone.com/articles/designing-docling-studio"
+        target="_blank"
+        rel="noopener noreferrer"
+        class="about-link"
+      >
+        <svg viewBox="0 0 20 20" fill="currentColor" class="about-link-icon">
+          <path
+            d="M9 4.804A7.968 7.968 0 005.5 4c-1.255 0-2.443.29-3.5.804v10A7.969 7.969 0 015.5 14c1.669 0 3.218.51 4.5 1.385A7.962 7.962 0 0114.5 14c1.255 0 2.443.29 3.5.804v-10A7.968 7.968 0 0014.5 4c-1.255 0-2.443.29-3.5.804V12a1 1 0 11-2 0V4.804z"
+          />
+        </svg>
+        {{ t('settings.designArticle') }}
+        <svg viewBox="0 0 20 20" fill="currentColor" class="about-link-external">
+          <path
+            d="M11 3a1 1 0 100 2h2.586l-6.293 6.293a1 1 0 101.414 1.414L15 6.414V9a1 1 0 102 0V4a1 1 0 00-1-1h-5z"
+          />
+          <path
+            d="M5 5a2 2 0 00-2 2v8a2 2 0 002 2h8a2 2 0 002-2v-3a1 1 0 10-2 0v3H5V7h3a1 1 0 000-2H5z"
+          />
+        </svg>
+      </a>
+    </div>
   </div>
 </template>
 
 <script setup lang="ts">
+import { computed } from 'vue'
 import { useSettingsStore } from '../store'
+import { useFeatureFlagStore } from '../../feature-flags/store'
 import { useI18n } from '../../../shared/i18n'
 
-const version = __APP_VERSION__
 const store = useSettingsStore()
+const featureStore = useFeatureFlagStore()
+const version = computed(() => featureStore.appVersion)
 const { t } = useI18n()
 </script>
 
@@ -118,4 +146,35 @@ const { t } = useI18n()
   color: var(--text);
   font-family: 'IBM Plex Mono', monospace;
 }
+
+.about-link {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  font-size: 13px;
+  color: var(--text-secondary);
+  text-decoration: none;
+  padding: 8px 12px;
+  border: 1px solid var(--border);
+  border-radius: var(--radius-sm);
+  background: var(--bg-elevated);
+  transition: all var(--transition);
+  width: fit-content;
+}
+.about-link:hover {
+  color: var(--accent);
+  border-color: var(--accent);
+  background: var(--accent-muted);
+}
+.about-link-icon {
+  width: 16px;
+  height: 16px;
+  flex-shrink: 0;
+}
+.about-link-external {
+  width: 12px;
+  height: 12px;
+  flex-shrink: 0;
+  opacity: 0.4;
+}
 </style>

frontend/src/shared/ui/AppSidebar.vue

@@ -97,10 +97,13 @@
 </template>
 
 <script setup lang="ts">
+import { computed } from 'vue'
 import { RouterLink, useRoute } from 'vue-router'
 import { useI18n } from '../i18n'
+import { useFeatureFlagStore } from '../../features/feature-flags/store'
 
-const version = __APP_VERSION__
+const featureStore = useFeatureFlagStore()
+const version = computed(() => featureStore.appVersion)
 const route = useRoute()
 const { t } = useI18n()